The present invention relates to a fixation clamp and, more particularly, to a fixation clamp for use in an external fixation system for holding bone fragments adjacent to each other.
External fixation systems are widely used to connect two or more bone fragments to each other. Such systems comprise bone screws, pins, wires which are inserted directly into the bone material and these systems use external structural elements as fixation rods, bars and rings. In order to connect the rods and bars to form a rigid frame, fixation clamps are used. Furthermore, fixation clamps are used to connect this screws and pins to the rigid frame to specifically hold bone fragments at an intended place.
One adjustable fixation clamp is known from U.S. Pat. Nos. 5,752,954 and 6,080,153, the disclosures of which are incorporated herein by reference, comprising two pairs of jaws allowing clamping of a rod as well as of a pin.
A clamp for multiple rod-shaped elements is known from U.S. Pat. No. 7,618,417, the disclosure of which is incorporated herein by reference, having one single pair of jaws. However, such a clamp allows clamping more than two, e.g. three or four rod-shaped elements such as pins with one single clamp, thus reducing the number of clamps. However, one further fixation clamp is necessary to fix the rod of said clamp to the frame of the fixation system.
U.S. Patent Publication No. 20060287652 discloses that the usual fixation clamps as e.g. known from U.S. Pat. No. 6,080,153 allow clamping of one single screw or pin to the frame and that this way to attach pins or rods leads to bulky fixation systems. Therefore U.S. Patent Publication No. 20060287652 discloses a fixation clamp addressing this problem and comprises two pairs of jaws within which each pair of jaws allows the introduction and clamping of two rods or pins etc. at the same time.
These clamps according to the prior art either provide different diameters of the reception cavities, such as grooves, provided by the jaws to introduce different sizes of rods, pins or wires, or they rely on additional inserts as e.g. disclosed in U.S. Patent Publication No. 20080065068. Such inserts reduce the diameter of the reception cavities to allow a secure fixing of differently sized rods, pins or wires.